1. Field of the Invention
The present invention is directed to a vacuum treatment apparatus for workpieces. More specifically the present invention is directed to a vacuum treatment apparatus for workpieces wherein a physical vapor deposition (PVD)-treatment or a chemical vapor deposition (CVD)-treatment or a plasma enhanced chemical vapor deposition PECVD or other hybrid treatment processes are performed.
2. Description of Prior Art
It is common to perform such vacuum treatment processes within vacuum chambers which define a unitary three-dimensional space, unitarily in all three dimensions and limited with respect to these three dimensions by respective walls.
Due to the arrangement of electrodes for plasma discharge, of gas inlet arrangements, as encountered especially for performing reactive treatment processes, and further of carriers for the workpieces etc. at distinct loci within such unitary chambers, it is difficult to fulfill the requirements of homogeneous treatment conditions for a multitude of workpieces to be simultaneously treated thereby additionally exploiting the volume of such chamber optimally by charging the highest possible number of such workpieces to be simultaneously treated to the chamber. In such known chambers and, dependent on the treatment process, to different extents, there occurs a gradient of treatment effect throughout the treatment chamber so that, in other words, a homogeneous equal treatment effect may only hardly be reached along substantial parts of such chamber volume.
From the German laid open document No. 22 41 634 which corresponds to the U.S. Pat. No. 3,856,654 a vacuum treatment apparatus is known with a treatment chamber for workpieces which is defined as an annular treatment chamber. The workpieces are supported at a cylindrical carrousel like and rotatable carrier arrangement within the annular treatment chamber. The workpieces are charged and discharged to the annular treatment chamber with a movement parallel to the axis of the chamber and are, workpiece by workpiece, fed to the carrier arrangement or removed therefrom. This is achieved by the action of a charging and discharging elevator which acts on the carrier at a predetermined fixed angular position of the carrier.
A drawback of this technique which is based on the principle of "first in, first out" is that a homogeneous undisturbed and steady treatment effect on the workpieces with which the annular chamber is charged may only hardly be realized primarily due to the disturbing effects due to the repeated charging and discharging operation for single workpieces at a predetermined angular position of the carrier.
It is further known from the U.S. Pat. No. 3,892,198 to provide a rotatably driven carrier bell for workpieces within a recipient of a vacuum treatment apparatus. The carrier bell is charged in that a substantial part of the cylindrical wall of the recipient is removable as a door. Thereby, the treatment chamber is not annularly which latter feature would only allow to minimize the volume of the treatment chamber for a predetermined number of workpieces to be simultaneously treated and to simultaneously realize an optimally uniform treatment effect along the entire pass of the workpieces as moved along the treatment chamber.